RegisterTask

class lsst.pipe.tasks.registerImage.RegisterTask(config: Config | None = None, *, name: str | None = None, parentTask: Task | None = None, log: logging.Logger | lsst.utils.logging.LsstLogAdapter | None = None)

Bases: Task

Task to register (align) multiple images.

The ‘run’ method provides a revised Wcs from matches and fitting sources. Additional methods are provided as a convenience to warp an exposure (‘warpExposure’) and sources (‘warpSources’) with the new Wcs.

Methods Summary

emptyMetadata()	Empty (clear) the metadata for this Task and all sub-Tasks.
fitWcs(matches, inputWcs, inputBBox)	Fit Wcs to matches.
getFullMetadata()	Get metadata for all tasks.
getFullName()	Get the task name as a hierarchical name including parent task names.
getName()	Get the name of the task.
getTaskDict()	Get a dictionary of all tasks as a shallow copy.
makeField(doc)	Make a lsst.pex.config.ConfigurableField for this task.
makeSubtask(name, **keyArgs)	Create a subtask as a new instance as the name attribute of this task.
matchSources(inputSources, templateSources)	Match sources between the input and template.
run(inputSources, inputWcs, inputBBox, ...)	Register (align) an input exposure to the template The sources must have RA,Dec set, and accurate to within the 'matchRadius' of the configuration in order to facilitate source matching.
timer(name[, logLevel])	Context manager to log performance data for an arbitrary block of code.
warpExposure(inputExp, newWcs, templateWcs, ...)	Warp input exposure to template frame.
warpSources(inputSources, newWcs, ...)	Warp sources to the new frame.

Methods Documentation

emptyMetadata() → None

Empty (clear) the metadata for this Task and all sub-Tasks.

fitWcs(matches, inputWcs, inputBBox)

Fit Wcs to matches.

The fitting includes iterative sigma-clipping.

Parameters:

matcheslist

List of matches (first is target, second is input).

inputWcslsst.afw.geom.SkyWcs

Original input Wcs.

inputBBoxlsst.geom.Box

Bounding box of input exposure.

Returns:

wcs: lsst.afw.geom.SkyWcs

Wcs fitted to matches.

getFullMetadata() → TaskMetadata

Get metadata for all tasks.

Returns:

metadataTaskMetadata

The keys are the full task name. Values are metadata for the top-level task and all subtasks, sub-subtasks, etc.

Notes

The returned metadata includes timing information (if @timer.timeMethod is used) and any metadata set by the task. The name of each item consists of the full task name with . replaced by :, followed by . and the name of the item, e.g.:

topLevelTaskName:subtaskName:subsubtaskName.itemName

using : in the full task name disambiguates the rare situation that a task has a subtask and a metadata item with the same name.

getFullName() → str

Get the task name as a hierarchical name including parent task names.

Returns:

fullNamestr

The full name consists of the name of the parent task and each subtask separated by periods. For example:

• The full name of top-level task “top” is simply “top”.

• The full name of subtask “sub” of top-level task “top” is “top.sub”.

• The full name of subtask “sub2” of subtask “sub” of top-level task “top” is “top.sub.sub2”.

getName() → str

Get the name of the task.

Returns:

taskNamestr

Name of the task.

See also

getFullName

getTaskDict() → dict[str, weakref.ReferenceType[lsst.pipe.base.task.Task]]

Get a dictionary of all tasks as a shallow copy.

Returns:

taskDictdict

Dictionary containing full task name: task object for the top-level task and all subtasks, sub-subtasks, etc.

classmethod makeField(doc: str) → ConfigurableField

Make a lsst.pex.config.ConfigurableField for this task.

Parameters:

docstr

Help text for the field.

Returns:

configurableFieldlsst.pex.config.ConfigurableField

A ConfigurableField for this task.

Examples

Provides a convenient way to specify this task is a subtask of another task.

Here is an example of use:

class OtherTaskConfig(lsst.pex.config.Config):
    aSubtask = ATaskClass.makeField("brief description of task")

makeSubtask(name: str, **keyArgs: Any) → None

Create a subtask as a new instance as the name attribute of this task.

Parameters:

namestr

Brief name of the subtask.

**keyArgs

Extra keyword arguments used to construct the task. The following arguments are automatically provided and cannot be overridden:

• config.

• parentTask.

Notes

The subtask must be defined by Task.config.name, an instance of ConfigurableField or RegistryField.

matchSources(inputSources, templateSources)

Match sources between the input and template.

The order of the input arguments matters (because the later Wcs fitting assumes a particular order).

Parameters:

inputSourceslsst.afw.table.SourceCatalog

Source catalog of the input frame.

templateSourceslsst.afw.table.SourceCatalog

Source of the target frame.

Returns:

matches: list

Match list.

run(inputSources, inputWcs, inputBBox, templateSources)

Register (align) an input exposure to the template The sources must have RA,Dec set, and accurate to within the ‘matchRadius’ of the configuration in order to facilitate source matching. We fit a new Wcs, but do NOT set it in the input exposure.

Parameters:

inputSourceslsst.afw.table.SourceCatalog

Sources from input exposure.

inputWcslsst.afw.geom.SkyWcs

Wcs of input exposure.

inputBBoxlsst.geom.Box

Bounding box of input exposure.

templateSourceslsst.afw.table.SourceCatalog

Sources from template exposure.

Returns:

resultlsst.pipe.base.Struct

Results as a struct with attributes:

matches

Matches between sources (list).

wcs

Wcs for input in frame of template (lsst.afw.geom.SkyWcs).

timer(name: str, logLevel: int = 10) → Iterator[None]

Context manager to log performance data for an arbitrary block of code.

Parameters:

namestr

Name of code being timed; data will be logged using item name: Start and End.

logLevel

A logging level constant.

See also

lsst.utils.timer.logInfo

Examples

Creating a timer context:

with self.timer("someCodeToTime"):
    pass  # code to time

warpExposure(inputExp, newWcs, templateWcs, templateBBox)

Warp input exposure to template frame.

There are a variety of data attached to the exposure (e.g., PSF, PhotoCalib and other metadata), but we do not attempt to warp these to the template frame.

Parameters:

inputExplsst.afw.image.Exposure

Input exposure, to be warped.

newWcslsst.afw.geom.SkyWcs

Revised Wcs for input exposure.

templateWcslsst.afw.geom.SkyWcs

Target Wcs.

templateBBoxlsst.geom.Box

Target bounding box.

Returns:

alignedExplsst.afw.image.Exposure

Warped exposure.

warpSources(inputSources, newWcs, templateWcs, templateBBox)

Warp sources to the new frame.

It would be difficult to transform all possible quantities of potential interest between the two frames. We therefore update only the sky and pixel coordinates.

Parameters:

inputSourceslsst.afw.table.SourceCatalog

Sources on input exposure, to be warped.

newWcslsst.afw.geom.SkyWcs

Revised Wcs for input exposure.

templateWcslsst.afw.geom.SkyWcs

Target Wcs.

templateBBoxlsst.geom.Box

Target bounding box.

Returns:

alignedSourceslsst.afw.table.SourceCatalog

Warped sources.